From: John 5:33-36
Christ Defends His Action (Continuation)
(Jesus said to the Jews,)  "You sent to John, and he has borne witness to the truth.  Not that the testimony which I receive is from man; but I say this that you may be saved.  He was a burning and shining lamp, and you were willing to rejoice for a while in his light.  But the testimony which I have is greater than that of John; for the works which the Father has granted Me to accomplish, these very works which I am doing, bear Me witness that the Father has sent Me."
31-40. Because Jesus is Son of God, His own word is self-sufficient, it needs no corroboration (cf. 8:18); but, as on other occasions, He accommodates Himself to human customs and to the mental outlook of His hearers: He anticipates a possible objection from the Jews to the effect that it is not enough for a person to testify in his own cause (cf. Deuteronomy 19:15) and He explains that what He is saying is endorsed by four witnesses--John the Baptist, His own miracles, the Father, and the Sacred Scriptures of the Old Testament.
John the Baptist bore witness that Jesus was the Son of God (1:34). Although Jesus had no need to have recourse to any man's testimony, not even that of a great prophet, John's testimony was given for the sake of the Jews, that they might recognize the Messiah. Jesus can also point to another testimony, better than that of the Baptist--the miracles He has worked, which are, for anyone who examines them honestly, unmistakable signs of His divine power, which comes from the Father; Jesus' miracles, then, are a form of witness the Father bears concerning His Son, whom He has sent into the world. The Father manifests the divinity of Jesus on other occasions--at His Baptism (cf. 1:31-34); at the Transfiguration (cf. Matthew 17:1-8), and later, in the presence of the whole crowd (cf. John 12:28-30).
Jesus speaks to another divine testimony--that of the Sacred Scriptures. These speak of Him, but the Jews fail to grasp the Scriptures' true meaning, because they read them without letting themselves be enlightened by Him whom God has sent and in whom all the prophecies are fulfilled: "The economy of the Old Testament was deliberately so orientated that it should prepare for and declare in prophecy the coming of Christ, Redeemer of all men, and of the Messianic Kingdom (cf. Luke 24:44; John 5:39, 1 Peter 1:10), and should indicate it by means of different types (cf. 1 Corinthians 10:11). [...] Christians should accept with veneration these writings which give __expression to a lively sense of God, which are a storehouse of sublime teaching on God and of sound wisdom on human life, as well as a wonderful treasury of prayers; in them, too, the mystery of our salvation is present in a hidden way" (Vatican II, "Dei Verbum", 15).
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland.
Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.